Drill-holder.



H0 MODEL.

I PATENTED MAY 31, 1904. A. c. KIMBALL & 0. BENSON.

DRILL HOLDER.

APPLIOATION FILED JULY 30, 19os.'

Lm|o.. WASNXNGTON o c ,UNITED STATES Patented May 31, 1904.

PATENT OFFICE.

ANDREW C. KIIVIBUALL, OF KEARNEY, AND CHARLES BENSON, OF NEWARK, NEWJERSEY; SAID KIMBALL ASSIGNOR TO SAID BENSON.

DRILL-HOLDER- SPECIFICATION forming part of Letters Patent No. 761,501,dated May 31, 1904. Application filed July 30, 19(l3, Serial No.167,642. (No model.)

To all whom, it may concern:

Be it known that we, ANDREW C. KIMBALL, a resident of Kearney, county ofHudson, and CHARLES BnNsoN, a resident of Newark, county of Essex, Stateof New Jersey, citi- Zens of the United States of America, have inventedcertain new and useful Improvements in Drill-Holders, of which thefollowing is a specification.

Our invention relates to drillholders used in lathe and drill arbors forapplying drills of diflerent sizes to the sockets of the arbors which ofnecessity are limited to one size for each arbor; and it consists of theimproved con struction hereinafter described and claimed, referencebeing made to the accompanying drawings, in which Figure 1 is a sideview of our improved holder with a drill inserted. Fig. 2 is mainly alongitudinal section of the holder, also with a drill inserted. Fig. 3is a side view of one of the parts of the holder on a larger scale.

The common holder is a taper socket for reception of the drill and ataper shank for inserting in the taper socket of the arbor, with a tipofangular cross-section on the upper end of the shank for engaging acorrespond-.

ingly-angular upper termination of the socket of the arbor, made insolid integral construction in which there 'is no compensation for theslack that occurs by wear of the socket of the holder and the shank ofthe drill in use, which causes frequent breakages of the tips ofthedrills, whichwe seek to avoid by our improvements, which are asfollows:

Our holder consists of two parts, one of which comprises a taper shankpart a, same as the ordinary holder for inserting in the lathe or drillarbor socket, and a split taper socket b for receiving-the shank 0 ofthe drill, the exterior contour of the split socket being tapered fromthe mouth upward a short distance, and between the upper end'of thiseX-' terior taper and the base of the shank a is ascrew-threadeds'ection d. The other part of i the holder comprises asleeve '6, having a flaring socket f in one end and aninternallyscrew-threaded part f in the other end, this latter part beingfitted to work with the threaded section cl of the holder for shiftingthe sleeve lengthwise along the split socket by rotating the sleeve togrip and release the split part d according as the sleeve is shiftedalong one way or the other. Shank a has the usual angular tip g forengaging in the corresponding angular upper terminal of the mandrelsocket for insuring rotation of the holder, and a like angular upperterminal 7b of the splitsocket is provided for like connection with thetip c' of the drill The threads of section d and of the sleeve-areinclined in respect of their spiral pitch reversely to the direction ofrotation ofthe holder, and thus whatever torsional stress there may beon the sleeve in action tends to maintain tightness of the holder.

, It will be seen that tightness of the drillshank in the socket of theholder will thus be insured against any slackness liable to occur bywear, and a common fault in the use of solid holdersviz., the droppingof the drill in an upright holder when a little worn and when not underfeeding pressurewill be avoided, as a retaining-grip by the split socketcan always be insured.

An essential advantage of the'construction is that there is always apowerful frictional grip of the jaws of the split socket on thedrill-shank, Which largely reinforces the driving power applied to thedrill by the tip 2', and thus relieves the excessive stress on thedrill-tips, especially when slack in the socket,

and thereby prevents the frequent breaking of these tips above alludedto.

The sleeve and the socket part are each duly slotted transversely, asshown at f and 76, respectively, for. the application of a drift 01starting the drills in case of being stuck ast.

What we claim as our invention is The combination in a drill-holder ofthe Signed at Newark, New Jersey, this 20th taper shgnk havirliig the1split socket of she day of July, 1903. oWer en externa yan internayupwar ly tapered, and provided With the lefthand 5 screw-threadedsection intermediate of the socket and the shank, and the sleeve haizingWitnesses: the upper internally left-hand screw-threaded JACOB D.KIEDINGER, socket and the lower flaring socket. EDWARD H. LOVING.

